Air brake control valve mechanism



Jan. 10, 1956 J.R. SNYDER 2,730,409

AIR BRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 9Sheets-Sheet l INVENTOR. 4605 E05 SNYDEQ Jan. 10, 1956 J. R. SNYDER AIRBRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 v 9Sheets-Sheet 2 Jan. 10, 1956 J. R. SNYDER AIR BRAKE CONTROL VALVEMECHANISM 9 Sheets-Sheet 3 Original Filed June 9, 1949 INVENTOR. J4mePas/l 5N vaeR Jan. 10, 1956 J. R. SNYDER 2,730,409

AIR BRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 9Sheets-Sheet 4 INVEN TOR. fleas AusH SNYDER A rrae/vsys J. R. SNYDER2,730,409

AIR BRAKE CONTROL VALVE MECHANISM 9 Sheets-Sheet 5 Jan. 10, 1956Original Filed June 9, 1949 A rmen/5V5 Jan. 10, 1956 J. R. SNYDER AIRBRAKE CONTROL VALVE MECHANISM 9 SheetsSheet 6 Original Filed June 9 INVEN TOR. USZflS/Y Arroe Jan. 10, 1956 J. R. SNYDER 2,730,409

AIR BRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 9Sheets-Sheet '7 EDM W ,4 7- TORNE ys t m jm 4, N 6 mar /f4 QM I .3 A w Ix 8 ,x (& l I m I 1 J M B Wm v? Q A aw & a? @m w a MNN Jan. 10, 1956 J.R. SNYDER 2,730,409

AIR BRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 9Sheets-Sheet 8 &

IIIIIIIIIIIIIHI'HIIIH 504 505 INVENTOR. 50.5 J4me Ausw fi/woee BYMQ", pI I K A Arne/v Jan. 10, 1956 .1. R. SNYDER 2,730,409

' AIR BRAKE CONTROL VALVE MECHANISM Original Filed June 9, 1949 9Sheets-Sheet 9 Q m Q Q 6% I was 1 2,730,409 Ice rimmed Jan. 10, 19562,130,409 AIR BRAKE CONTROL VALVE MECHANISM Jacob RushSnyder,-Cleveland, Ohio Application March 4, 1952, Serial No. 274,777

13 Claims. c1. 303-68) This invention relates to fluid pressure brakesand, more particularly, to improved air brake apparatus for I use onrailway freight cars or other vehicles.

:ThiS application is a division of original application Serial No.98,063, filed June 9, 1949.

qAn object of the present invention is to provide an improved'air brakecontrol valve mechanism which will function in an eificient and reliablemanner under all operating conditions and which is of a relativelysimple construction as compared with certain other control valvemechanisms provided heretofore.

Another object of this invention is to provide an improved. air brakecontrol valve mechanism embodying an application chamber and a relayvalve means responsiveto application chamber pressure for controlling-of the relay valve means and a normally open valve adapted to be closedfor preventing the loss of reservoir pressure.

Additionally, this invention provides an improved air brake controlvalve mechanism of the character above indicated in'which the manuallyoperable vent means is movable to one position for venting the relayvalve piston chamber and is further operable to a second position forventing the reservoir.

It is a further object of this invention to provide novel valve' meansfor relieving the emergency piston of fluid pressure on the brake pipeside thereof to increase the effectiveness of the emergency piston inopening the emergency vent valve.

.Thelinvent'ion can be further briefly summarized as consisting incertain novel combinations and arrangements of parts hereinafterdescribed in greater detail and particularly set out in the claimshereof.

In the accompanying sheets of drawings,

Fig. 1 is a diagrammatic view showing the improved air brake apparatusapplied to a freight car and embodying hydraulic pressure means forrendering the control valve mechanism automatically responsive tochanges in the" load of the car;

Fig.2 is a longitudinal section, somewhat diagrammatic in form, takenthrough the control valve mechanism of the air brake apparatus of Fig.l, the control valve mechanism being shown in released and normalcharging position and with the load responsive mechanism at.half-loadsetting;

Fig. 3 is a fragmentary view of the mechanism corresponding with theportion of Fig. 2 in which the service and emergency pistons are locatedbut showing this portion of the mechanism on a larger scale;

Fig. 4 is a fragmentary view of the control valve mechanismcorresponding with the portion of Fig. 2 in which the load responsivemeans and the relay valve means are located but showing this portion ofthe mechanism on a larger scale;

Fig. 5 is a fragmentary view of the control valve mechanismcorresponding with the portion of Fig. 2 in which certain of thecharging valves and manually operable vent valves are located butshowing this portion of the mechanism on a larger scale;

Fig. 6 is a larger scale fragmentary longitudinal section showing theservice piston and the mechanism adjacent thereto;

Fig. 7 is a larger scale fragmentary longitudinal section showing theemergency piston and the mechanism adjacent thereto;

Fig. 8 is a transverse section taken through the control valve mechanismat the location indicated by section line 8--8 of Fig. 2;

Fig. 9 is a larger scale fragmentary longitudinal section taken throughthe application chamber vent valve;

Fig. 10 is alarger scale fragmentary detail view in longitudinal sectionshowing the application chamber inlet valve in the second stageemergency position;

Figs. 11 and 12 are fragmentary sectional views taken respectively onsection lines 11-11 and 12-12 of Figs. 3 and 7 and further illustratingthe quick-service venting means;

Fig. 13 is a fragmentary vertical section showing a gauge means beingused to determine the setting of the load responsive mechanism;

Fig. 14 is a larger scale fragmentary longitudinal sec tion takenthrough the emergency piston and the mechanism adjacent thereto andshowing a modified construction; and

Fig. 15 is a larger scale fragmentary longitudinal section of theportion of the mechanism in which the relay valve mechanism is locatedand showing a modified construction.

General arrangement In the diagrammatic illustration of Fig. 1, theimproved air brake apparatus is shown applied to a railway car 10 havingwheeled trucks which include side frames 11 constituting unsprungportions of the car and a bolster 12 constituting a sprung portion ofthe car. The air brake apparatus here shown includes a brake pipe 13, acontrolvalve mechanism 14, a supply reservoir 15 and a brake cylinder16. The brake pipe 13 includes the usual flexible hose members 17 and 18adapted for connection with adjacent cars and is also provided withconventional angle cocks 19 and 20. This air brake apparatus alsoincludes a conventional retaining valve 21 which is connected with thecontrol valve mechanism 14 by the pipe 22. The supply reservoir 15 andthe brake cylinder 16 are connected, respectively, with the controlvalve mechanism 14 by the pipes 23 and 24. The railway car 10 isprovided with hydraulic pressure generating devices 25 and 26 whichconstitute a part of a load-responsive mechanism and will be describedin greater detail hereinafter. These hydraulic pressure generatingdevices are connected with the control valve mechanism 14 by a pipe line27 which includes branch pipes 25a and 26a.

The control valve mechanism The control valve mechanism 1 4 will now bedescribed in greater detail and, from Figs. 1 and 2, it will be seenthat the housing of this mechanism comprises three sections 28, 29 and30 of which the section 28 is an interwpeq mediate section and thesections 29 and 30 constitute end sections which are connected toopposite sides of this intermediate section. The intermediate section 28also constitutes a mounting bracket adapted to be bolted or otherwiseattached to the structure of the car for mounting the control'valvemechanism 14 thereon. The housing section '29 comprises'a hollow memberor bulb having therein a chamber 31 which serves as the auxiliaryreservoir. The housing section is also in the form of a hollowmember'or' bulb having a chamber '32 therein which serves as a controlchamber and is conveniently referred to as an application chamber. Thehousing section'29 also contains a service piston 33 andanemergeneypiston 34. The housing section 30 also contains a relay'valvemechanism 35 which will be further described hereinafter.

'The'intermediate housing section 28 'is provided with substantiallyfiat faces 36 and 37 on opposite sides thereof against which the endhousing sections 29 and 30 are bolted or otherwise secured. Between theside: faces 36 and 37 the intermediate'housing section 28 is providedwith afulcrum chamber 38, an exhaust chamber 39 a'ndfa control chamber40. The'latter chamber is here inafter referred to at times as anemergency and release control chamber or simply as a control chamber.The intermediate housing section 28 is also provided at a suitable'pointthereof with tapped openings with which the above-mentioned pipes 13;22,23 and 24 are connected. as shown i'n FigJZ'. This housing section isalso provided with a passage-39a connecting the exhaust cham- Ber '39with atmosphere and which passage 'is' controlled by a' suitable insectguard'41. l

' The housing section 29 of the control valve mechanism 14 is closed atits inner end by a generally flat substantially disk-shaped member 42which, as hereinafter described, constitutes a carrier'for certain ofthe valve devices. The carrier 42 cooperates with the housing section 29in defining the auxiliary reservoir 31 and can be connected with theopen end of this housing section by being snugly seated in a counterbore43. The depth of the counterbore 43 is such that the outer face of thecarrier 42 will be substantially flush with the end face of the housingsection 29 and when the latter is connectedwith the intermediate housingsection 28, the outer face of the carrier will be clamped against thefiat face 36 of the intermediate housing section. A sheet 44 of suitblsa s tmat r a m y. bepmvid d between the carrier 42and the intermediatehousing section 28.

The carrier 42 also forms a support for an adapter member 5 aa av .0dvhaving a ov 7 h n. The adapter member 45 is a substantially flat,disk-like member located between the body 46 and the carrier 42. Thebody 46 is provideclat its inner end with a disk-like a e pqrtioa fil etinane. u s a l y fl c in ne sement i h h adjac n ace of e pt r. m mrtS-As how in H s 2 he ody 46 a d. i cov r 4.7 ccpe tq n efiniaaa P131011.chamber 49 n'w ch the ve tQI BQ ate T he erv ce P st n f rm d,

nse t, by. apa of co pera n is m bers d. 51.

and, in P rt y a fl xibl aphra m 52 w os er pQ tions are clamped betweenthe body 46 and the cover 47. e. ent a PQ iiQI of h iaphra m te ds acrthe chamber 49 and divides the same into a pair of cornp ttm i 1 sl d,54- Th Pi ton. member .50. .5 r

m d a inst opp s t id s Of. the en ra RQIIiQL c e aphra m s mea of aampin n t h mpartme t i n. onensomm qa ion w h. e iliary reservoir 31through the passage 56 and the compartment 54 is in direct communicationwith a chamber 57 which can be conveniently termed a brake pipe chamber.A passage 58 provided in the intermediate housing section 28iconne'cts'the brake pipe chamber 57 with the brake pipe connection 13.

The carrier 42 and the adapter member 45 cooperate in defining a chamber59 in which the emergency piston 34 is located. The emergency pistonchamber 59. lies inwardly of the service piston chamber 49, but islocated in substantially coaxial relation to the service piston chamber.The emergency piston 34 is formed, in part, by a pair of piston members60 and 61 and, in part, by a flexible diaphragm 62 extending across theemergency piston chamber and dividing the latter into compartments 63and 64. The outer portions of the diaphragm 62. are clamped between thecarrier 42 and the adapter member 45 and the central portion of thisdiaphragm is clamped between the piston members 60 and 61. Thecompartment 63 of the emergency piston chamber is indirect communicationwith the emergency and release control chamber 40 through a passage 65formed in the intermediate housing section 28. The compartment 64 is indirect communication with the brake pipe chamber 57 through the passage66 of the adapter member 45.

The service piston The service piston 33 is supported and guided formovement axially of the chamber 49 by means of a 'pair of axially spacedbearing holders 67 and 68. The bearing holder 67 is in the form ofasleeve having a central passage 69. therein and having substantiallyradially'projecting arms 70 by which this bearing holder is mounted onposts/Z1 of the body 46 and secured to such posts by screws 72. Thepiston member 50 of the service piston 33 is provided with a central hubportion 73 having therein a valve chamber 74 into which a sleeveportion'75 of the bearing holder 67 extends. A bushing 76 mounted on thesleeve portion forms a bearing on which the hub portion 73 of the pistonmember 50 is slidably guided.

The bearing holder 68 is formed as an axial extension of the cover 47 ofthe body 46 and has a bushing 77 mounted therein. The hub portion 73 ofthe piston member 50 has a tubular integral extension 78 formed thereonwhich extends into the bearing holder 68 and is slidably guided in thebushing 77. The extension 78 has an axial passage 79 therein which atits inner end is connected with the valve chamber 74 of the hub portion73.

The service piston 33 is shown in Figs. 2 and 3 as being in its releaseor normal charging position. Movement of the piston toward this positionis limited by a yieldable abutment or stop which, in this instance, isin the form of a ring 88 which is slidable in an axial chamber 81 of.

the cover 47. and which sliding movement is resisted by a compressionspring 82 located in this chamber. The spring 82 is maintained undercompression in the chamber 81 by providing the wall of the latter withan internal groove in which a locking ring 83 engages and forms a stopagainst which the abutment ring is held by the spring.

The connection of the passage 79 of the service piston stem 78with thevalve chamber 74 is controlled by a charging valve 84 which cooperateswith a valve seat 85 extending around the inner end of the passage 79.The valve 84 is carried by a plunger 86 which is slidable in the passage79. The valve 84 is normally held'in its closed position by a spring 87seating in an axial recess of the bearing holder 67. Opening of thevalve 841is accomplished by movement of the piston 33 toward the left asseen in Figs. 3 and 6 which causes the valve seat 85 to move away fromthe valve 84. For a purpose to be presently explained another plunger 88is providedat the outer end of the plunger 86 and has a head ssa slidable in the passage 79 of the service piston stem 78. A

spring 89 is located in an axial recess 90"of theplu nger 86 and acts onthe head'88a to urge the plunger SSi'nj'a direction axially outwardly ofthe piston stem '78 (toward the left'as seen in Figs. 3 and 6). Closingof the valve 84'is accomplished by movement of the piston 33'jtov v'ar dof the piston 33 during service applications of the brake. The spring 91is preloaded by being confined between a pair of spring seats 92 and 93which are prevented from moving apart more than a fixed distance by thetie rod 94.

Air supplied to the brake pipe chamber 57 by the brake pipe 13' passesdirectly into the compartment 54 of the service piston chamber 49 andthen through the radial passage 6721 of the bearing holder 67 into thevalve chamber 74 of the service piston 33. When the valve 84 is open,brake pipe pressure then passes directly from the valve chamber 74 intothe passage 79 for delivery into the auxiliary reservoir 31. The flow ofair from the passage 79 into the auxiliary reservoir takes place througha group of radially extending charging ports 95 of the piston stem 78and also through a continuously open equalizing" port or orifice 96. Thecharging ports 95 communicate with an annular groove 97 extending aroundthe piston stem 78 and are controlled by an annular valve member 98located in this groove.

The valve member 98 is here shown as being an elastic band formed ofrubber or other elastic material. The groove 97 is preferably formedwith inclined outwardly divergent side walls and the elastic valvemember 98 is formed with similar convergently inclined side edges whichseat against the inclined side Walls of the groove.

When the pressure in the auxiliary reservoir 31 is materially lower thanthe pressure in the brake pipe chamber 57 and the valve 84 is open, thebrake pipe pressure flows through the ports 95 and unseats the valvemember 98 to permit a relatively rapid charging of the auxiliaryreservoir. When the pressure of the auxiliary reservoir 31 approaches orreaches the pressure of the brake pipe chamber 57, the valve member 98thereafter remains seated'and small or gradual pressure changesoccurring in the brake pipe are equalized with the auxiliary reservoirthrough the equalizing port 96.

The fluid pressure in the application chamber 32 is supplied theretofrom the auxiliary reservoir 31 and for this purpose the intermediatehousing section 28 of the control valve mechanism 14 is provided with apassage 99 which also extends through the carrier 42, the adapter member45, the body 46 and the cover 47. The discharge end of the passage 99 isnot connected with the application chamber 32 directly but through thevalve chamber 182 as hereinafter described, or through the valve chamber182 and the piston chamber 179a of the relay valve means as shown in themodified construction of Fig. 15. The delivery of pressure fluid to theapplication chamber 32 from the auxiliary reservoir 31 through thepassage 99 is controlled by an inlet valve or application chamber supplyvalve 100 which is carried by the plunger 88 and cooperates with a valveseat 101 formed on a screw plug 102 which is mounted in the outer end ofthe bearing holder extension 68 of the cover 47. The screw plug 102 isadjustable in the extension 68 for properly locating the valve seat 101and has an axial passage 103 therein which communicates with theauxiliary reservoir through a port 104. The passage 103 of the plug 102is connected with the supply passage 99 to the application chamberthrough a bent tube 105. As shown in Fig. 3, the tube 105 has one endthereof secured in the outer end of the passage 99 as by the solder105a, or by a suitable clamping and packing means (not shown), and hasits other end engaged in the passage 103 of the plug 102 and sealedtherein by means of the packing 106.

When the service piston 33 is in its release or chargingposition, theinlet valve 100 is in its closed position in engagement with the valveseat 101 and is maintained in such closed position by the action of thespring 89 on the plunger 88. Upon the occurrence of service andemergency reductions in brake pipe pressure, the service piston 33 isshifted toward the right by the pressure differential of the auxiliaryreservoir 31 and brake pipe chamber 57 acting thereon and this causesthe inlet valve 100 to be opened to supply pressure fluid through thepassage 99 to the application chamber, as will be more fully ex stemextension 107 of reduced size which extends through the port into thepassage 103 and carries a head 108 which serves as a restricting elementor choke member. During service applications of the brake, the piston 33moves toward the right against the action of the spring 87, but movementof the piston in this direction is limited by the preloaded spring 91which acts as a stop. During movement of the piston 33 within thedistance permitted by the stop 91, the valve will be disengaged from theseat 101 to permit pressure fluid from the auxiliary reservoir 31 toflow into the pipe through the port 104 and, in surrounding relation tothe stem 107. The preloaded spring 91 serves very well as a stop, asjust described above, but can be omitted if desired since a satisfactoryactuation of the valve 100 will be obtained even if no stop is employed.

When an emergency application of the brake is made, the differentialpressure acting on the piston 33 is of a substantially greater forcethan during a service application and causes the piston to compress thepreloaded spring 91 as well as the spring 87. This greater movement ofthe piston 33 during the emergency application causes the valve 100 tobe disengaged from the seat 101, as

just explained above, but also continues to move the plunger 88, causingthe restricting head 108 to be moved into the port 104 to the positionshown in Fig. 10. The diameter of the head 108 is of a size relative tothe diameter of the port 104 such that only a small annular clearanceremains therebetween forming a restricted connection beportions 109 and109a of which the latter communicates with a vent chamber 110 and iscontrolled by a vent valve 4 111. The vent chamber 110 is alwaysconnected with the exhaust chamber 39 through the passage 110a. The ventvalve 111 is mounted in a chamber 112 constituting an enlargement of thepassage 109 and is preferably in the form of a self-contained valvedevice of the kind used in the inflating stems of pneumatic tires. Thisvalve de vice comprises a valve body or barrel 113 having a thread-' edhead 113a thereon by which the valve device is mount ed in the chamber112 and a valve element 114 normally: in engagement with the inner endof the, barrel 113 for closing the passage extending through the barrel.The

valve element 114 is adapted to be moved away from the 7 end of thebarrel 113 for opening the passage by means of a valve stem 115. A lightspring 116 contained in the barrel 113 normally holds'valve element 114in its closed position and in this instance is also held in its closedposition by an additional spring 117 which is located in the valvechamber 112 externally of the valve device 111.

During the release of the brake following either a service or anemergency application, the increasing pressure in the brake pipe and inthe brake pipe chamber 57 shifts the piston 33 toward the left and thismovement of the piston is used to shift the valve element 114 'to itsopen positionfor venting the application chamber to the vent chamber110. To utilize this movement of the piston 33 for this purpose, a. pairof aligned plungers 118 and 119 are provided on opposite sides of thediaphragm 52 and are slidable, respectively, in the body 46 and thecover 47. The. plunger 118 is in engagement with the valve actuatingstem 115, as seen in Figs. 3 and 17, and when movement is right, thevent valve '111 is opened.

imparted to shift the plungers 118 and 119 toward the.

Motion is transmitted from the piston 33 to the plunger a 119 through abell crank lever 120 mounted on a pivot an: 121, his h l -s a her. h aarm ,2 1; h h.

cooperates with the stem extension 78 of thepiston33, Th ,1 4 i nrqvitsd. tt en thereof with n t i k ibs. ement Q 1 s. 2.adaptsd t s oner.- tw th ca nshq lsis 123 s ftr ss y the tem ex n ion "T s tii t as zaio t eb l -s v has a fiksd. s in -Whi h. a t se ssttti ii t in sm unt d ah te. iinsf nd 9 th s h ust. Pin' as a. r du s p t: tier l 2gajengaging ina recess 125 provided in the outer at eithsahaisalfi- .Duiing movementofthe piston 33 toward the left in i '.bia s l hs h l stasis sv r .0 willbe rocked ts 1 6 i irecti n. t cause the plu e .8 o p theve'n t valve'Duringthe initial movement of the a oward theright during anapplication of the I, the bell cranlt lever 1 20 -will be rocked in acounterclockwise direction by the action of the spring 117 iiis f bnqvss hat alt mem 4 to t closed The emergency piston As mentioned above,the emergency piston 34 includes .f fci r f a i p dni i i srs n of whimember 60 is'p rovided with an enlarged central p rt1on126' having achamber 127 therein. These axial passas of a central extension portion132 of the carrier"4 2 .""l'he bushing 13 1 iSi mQtl I 1id in a cer tralo e -de ict For m t t P ton iri the bushings 13Qan'd. 131, the hubportion 126 of the ember'60. has a hollow stem extension 133 which o'wstem extension 134 which is: slidable in the 131'. The hollow stem 133ofthe piston member s anaxialpa'ssage'l35 therein and the stem extensionf'th."'niit 12.8. has an axial bore 13s therein. As n in Fig.'7, theendo f'thestem 133 has lingers 133a ith spaces or openings 1331therebetween.

' ner, 'end'fof the extension portion 132 of v the 421s provided with agroup of axially extending 1'31 which"support a bearing block 13$, Then'p'o tion 132 is also provided adjacent the base fine M 140 having astem 140a slidable in the 1g block 133 is normally held in engagementwith th valve seat l3j9 by a spring 141 but is adapted to he diseng'aged from such seat by the inner end of the hollow m' 133 durihgmovement of the emergency piston.34

"tioi shown in Ifigs. 3 and 7.. i

, ,pttrtirdrtv 1260i the emergency piston 34 has v eat formed thereon soas tobe locatedin the 'c mb'er 127. A check valve member 143 located be;127. cooperates with the seat 142 and is .31 held thereagainst by aspring 144 located in th b e or the nut extension 134. The check valve 143 is axially movable in the chamber 127 and during this movement byhaving'a stern 143a n the bore 136. i

is gu de na The emergency vent valve shown in Figs. 3 and 7 the body 46is provided.

embers are heldin clamped engagement with op in the bushing 1'30 and theclamping nut 128 V ers 13 7.w ith an annular valve seat 139. A

sbstantisi xhqut i ss hape his valve. iS el q v and.

is ar iscl y id r. .4 which, rn i mo n e on the inner end of. am axiallymovable stem 149, The stem .2 s i h n a b sh ng 5 o n ed n the sleeveportion 151 of the bearing holder 67. A spring 152 surrounding thesleeve portion 151 of the bearing holder 67. acts on the spider 148 forurging the balanced valve 147. towards its closed position.

During an emergency application of the brake the emer gency piston 34 isshifted suddenly toward the left, causing the end of the stem extension134 to engage the guide stem 149 of the balanced valve 147 and shiftthis valve to its open position in opposition to the spring 152. Theopening of the valve 147. causes the brake pipe chamber 57.and thecompartment 54 to be placed in direct communication with the ventchamber through the passage and through the hollow valve itself, tothereby quickly vent the brake pipe 13 to atmosphere.

The balanced valve 147 is a hollow annular member of substantiallyhourglass shape, as mentioned above; and has two seating portions 153and 154 thereon. The seating portion 153 is an annular strip-like memberwhich is bonded or otherwise connected to one of the convergentlysloping external annular faces of the valve. This seating element isformed of rubber or other suitable yieldable material and is engageablewith the annular seat 146 when the valve is in its closed position. Theother seating'elemen't 154 is a ring-shaped member of a taperedcross-sectional shape which'is bonded or otherwise connected to theinner end face of the valve member 147 and is adapted to seat against avalve seat which, in this instance, is provided by the flat surface ofthe adapter 45.' 'The seating element 154 is made ofrubber or othersuitable resilient material and is compressible against the adapter 45when thevalve 147 is moved to its closed position. This seating element154 has an axial thickness and yieldability such that during the closingmovement of the valve 147 it will engage the surface of the adapter 45and will be compressed or deflected thereagainst for an amount to permitgood seating engagement of the elemen t 15 3 against the annular valveseat 146.

Quick-service venting To accomplish a quick-service venting of the brakepipe 13, the control valve mechanism 14 is'provided with a quick-serviceventing means which will be described next. This quick-service ventingmeans comprises a valve seat 155 formed on the body 46 (see Figs. 3 and7) and a valve 'mernber 156 cooperating with such seat and adapted to bemoved to open position by the emergency piston 34. The valve seat 155 islocated around a vent passage 157 which includes a passage portion 157aformed inthe adapter 45 and connected with'the vent chamber llfl througha valve chamber 158 and a connecting passage 159 A The valve member 156is carried by a valve plate 160 which is slidable in a valve chamber 161of the body 46. A conical spring 162 located in the 'valve chamber 161acts on the valve plate 160 for normally holding the valve member 156 inengagement with the valve seat 155. The large outer end of the conicalspring 162is anchored on the body 46'by being engaged in an internalannular groove 163 of the valve chamber 161'. Move,- ment for openingthe valve member 156 is transmitted to the valve plate 160 from theemergency piston 34 by the push pins 164.

During a service application of the brake, an initial reduction of brake'pi'pe pressure is made by actuation of the engineers brake valve. Thisinitial reduction causes a movement "of 'the emergency piston towardftheleft, which is ordinarily an 'idle movement because it is insufficientto cause opening of the emergency" vent valve 9 147 but, in accordancewith this invention, this movement of the emergency piston is utilizedto cause opening of the vent valve 156 for producing a quick-serviceventing of the brake pipe to the atmosphere.

The quick-service vent passage 157, 7a is also controlled by a valvemember 165 located in thevalve chamher 158 and which, in this case, iscarried by a portion 166 of the flexible diaphragm 62. A chamber 167formed in the carrier 42 and located on the opposite side of thediaphragm 62 is always in direct communication with the passage 99, andhence, is subject to the pressure of the application chamber 32 Wheneverpressure is supplied to the latter through the passage 99. Therefore,whenever application chamber pressure builds up in the chamber 167 itflexes the diaphragm portions 166 on which the valve member 165 ismounted and holds this valve member in seating engagement to close thequickservice vent passage 157a. However, when the quickservice ventvalve 156 is opened by the initial movement of the emergency piston 34,as explained above, brake pipe pressure flows through the quick-servicevent passage 157, 157a causing opening of the valve member 165 andproducing a quick-service venting of the brake pipe into the ventchamber 119, and this quick-service venting continues until applicationchamber pressure builds up sufficiently in the chamber 167 to close thevalve member 165.

The emergency and release control chamber The emergency and releasecontrol chamber 48 is normally charged with pressure and when anemergency reduction occurs in the brake pipe, the pressure of thecompartment 64 of the emergency piston chamber 59 is reduced. Therelease control chamber 40 is in direct communication with thecompartment 63 through the connecting passage 65. The resulting pressurediflerential between the compartments 63 and 64 causes the pressure ofthe release control chamber 40 to act on the emergency piston 34,shifting the latter quickly toward the left to cause opening of theemergency vent valve 147. The opening of this vent valve produces arapid emergency venting of the brake pipe which results in a quickmovement of both emergency and service pistons to the full emergencyposition and in the desired emergency functioning of the various otherparts of the apparatus which will be described hereinafter.

When the reduction in brake pipe pressure is only a service reduction,it is desirable to release the pressure of the control chamber 40 sothat this pressure will not cause an emergency actuation of the piston34 which would otherwise result in an undesired emergency application ofthe brake. For this purpose, a plurality of circumferentially spacedaxially extending leakage grooves 172 (see Fig. 7) are provided in theouter surface of the hollow stem 133 of the emergency piston 34 andextend for a portion of the length of this stem. The grooves 172 are ofa length such that their ends will overlap a counterbore 173 provided inthe bushing 130 when the emergency piston is in the release and normalcharging position shown in Figs. 2, 3 and 7. The grooves 172 are also inoverlapping relation to the counterbore 173 while the apparatus is inthe quick service'and service positions. During 'quick service andduring a service application of the brake the valve 140 remains closed.

Upon the occurrence of a service reduction in brake pipe pressure, thepressure in the control chamber 40 is relieved by the flow of fluidtherefrom through the grooves 172 and the counterbore 173 which are thenin communication. This escaping fluid then flows around the end of thehollow stem 133, as permitted by the fingers and openings 133a and 133b,into the passage 135. This release of pressure fluid from the controlchamber 40 into the brake pipe chamber 57 occurs while tion being madein brake pipe pressure but the control chamber 40 is of such smallvolume that the release of its pressure fluid into the brake pipechamber at this time produces no noticeable retardation of the brakepipe reduction being made. When an emergency reduction in brake pipepressure is made, the resulting movement of the emergency piston 34toward the left is of suificient extent to shift the groove 172 out ofregister with the counterbore 173, thereby temporarily trapping thepressure fluid in the control chamber 40 and the compartment 63 so thatit will be fully effective on the emergency piston 34 for shifting thelatter toward the left for the full travel for opening the emergencyvent valve 147. In accomplishing this function the grooves 17 2 and thecounterbore 173 thus serve as a valve means which remains open duringthe occurrence of a service reduction in brake pipe pressure but isautomatically closed during the occurrence of an emergency reduction.

After the emergency piston 34 has been shifted to the left to causeopening of the emergency vent valve 147 as the result of an emergencyreduction in brake pipe pressure, it is desirable to relieve thepressure in the control chamber 40 so that various other desiredfunctions of the apparatus can take place in proper sequence. Thepressure in the control chamber 40 is relieved at this time through aclearance space provided between the hollow stem 133 and the bushing andwhich space forms a leakage path through which this pressure fluid canescape and travel around the end of the stem into the passage 135. Theclearance provided between the hollow stem 133 and the bushing 130 forthis purpose can be on the order of a few thousandths of an inch, butcan be varied to suit the operating characteristics of the particularbrake mechanism in which it is provided.

The application chamber The housing member 30 is provided at the innerend thereof with a closure member or carrier 174 (see Figs. 2 and 4)which cooperates with this housing member in defining the applicationchamber 32. The member 174 is referred to as a carrier because itprovides a support for the relay valve mechanism 35 and for the ventvalves 175, 176 and 225 which will be described hereinafter. The carrier174 also forms a support to which an adapter member 177 is connected.The carrier 174 is an annular disk-like member having the outer edgethereof received in a counterbore 178 of the housing member 30 so thatwhen the latter is connected with the intermediate housing section 28,the carrier will be clampingly held against the face 37 of the latterwith a gasket 37a therebetween.

The relay valve mechanism The carrier 174 and the adapter 177 havecooperating portions which define a pair of piston chambers 179 and 180for the relay valve mechanism 35 and also define valve chambers 181 and182 for the vent valves and 176, respectively. A flexible diaphragm 183is clamped between the carrier 174 and the adapter 177 and forms agasket therebetween with portions of this diaphragm extending across thechambers 179 and of the relay valve mechanism 35 to constitute operatingportions of this relay valve means.

The relay valve mechanism 35 comprises pistons 184 and 185 (see Fig.4)'located in the chambers 179 and 180, respectively. The piston 184 isformed, in part, by a disk-member or head 184a and, in part, by aportion 183a of the diaphragm 183. The piston head 184a is carried by astem 186 which is slidable in a bushing 187 of the carrier 174. Thepiston 184 divides the chamber 179 into two compartments 179a and 17%,

through a leakage space formed by a clearance or toler- 11 anceproyidedbetween the stem 186' and, the bushing 187. 4

The piston 185 is formed, in part, by a disk or head 185a and, in part,by the diaphragm portion 18311. The piston head 185a is carried by astem 188 which is slidable in a bushing 1890f the carrier 174. Thepiston 185 divides the chamber 180 into two compartments 180a and 180b,of which the compartment 180a is a pressure compartment. The compartment180b, is vented to atmosphere through a leakage passage formed. by aclearance or tolerance provided between the stem 188 and the bushing189.

The relay valve mechanism 35 also includes a valve chamber 190 locatedadjacent thechamber 180 and connected therewith by a passage 191. Anannular valve seat 192 is formed on or carried by the adapter 177 and islocated in the valve chamber 190 in surrounding relation to the adjacentend of the connecting passage 191. A second annular valve seat 193 isformed on or carried by the adapter 177 at the other end of the passage191 and is located in the piston chamber 180. A valve 194 located in thevalve chamber 190 is nor mally held in engagement with the valve seat192 by the spring 195. The valve 194 is here shown as having a stem 196which is slidable in an axial bore 197 of a screw plug 198 which forms aclosure for the valve chamber.

A valve 199 in the form of a flat ring is provided in the piston chamber180 for cooperation with the annular valve seat 193. The valve 199 ismounted on the radial flange 200 of a cup-shaped valve carrier 201 whichis attached to the piston 185 by means of the shouldered screw 202. Thescrew 202 has a head portion 203 which is spaced from the piston bymeans of the intervening spacer or shoulder 204. The head portion 203 ofthe'screw is located in the cup-recess of the valve carrier 201 and thespacer portion 204 extends through an opening in the bottom of the valvecarrier. The wall of the cup-shaped portion of the valve carrier 201 hasopenings 201a therein which connect the passage 191 with the chamber180a when the valve member 199 is in engagement with the seat 193.

The valve carrier 201 has limited axial shifting movement on the spacer204 and relative to the piston 185 but is normally urged in a directionaway from the piston by the spring 205. The screw 202,also carries astem extension 206 formed as an integral, part of the head 203 and whichextends into the passage 191 and is engageable with the valve 194 forshifting the latter away from the valve seat 192 in opposition to thespring 195.

The piston 185 is normally shifted toward a retracted position by aspring 207, that is to say in a direction to permit closing of the valve194 and cause opening of the valve 199. The spring 207 has one endthereofin engagement with theadapter 17.7 in surrounding relation to thevalve seat 193 and its other end in en-' 209 which is pivoted on afulcrum pin 210. The lever 209 has arms 209a and extending in oppositedirections from the fulcrum pin 210 and engaging, re-

spectively, the piston stems 186 and 188. The fulcrum pin 210 is carriedby a bracket 211 which constitutes a part'of a load-responsive mechanism212 which is located in the fulcrum chamber 38 andwill b'efdescrlibedhereinafter;

Pressure fluid is supplied to the valve chamber 190 of the relay valvemeans 35 from the supply reservoir 15 through the pipe 23, the passage212 and the passage portions 213a and 213b. An annular groove 214 formedin the valve seat 193 is connected with the atmosphere through thepassage 215, the pipe 22 and the retaining valve 21. The compartment180a is connected with the brake cylinder 16 through the passage 216 andthe pipe 24, Pressure fluid is adapted to be supplied to the compartment179a of the valve chamber 179 from the auxiliary reservoir 31 throughpassage means which includes the above-mentioned passage 99 and thepassage portion 217.

Service application From the construction thus far described above itwill be seen that when a service reduction is made in brake pipepressure it causes actuation of the service piston 33 which causes thevalve to be opened to supply pressure fluid from the auxiliary reservoir31 through the passage 99 to the application chamber 30 and the relayvalve means 35. This results in fluid of substantially the pressurevalue of the application chamber 30 to be supplied to the compartment179a of the relay valve means 35 through the passage 217. This causes aworking stroke of the piston 184 toward the left, as seen in Fig. 4,which results in rocking of the lever 209 on the fulcrum pin 210. Therocking of this lever causes the piston 185 to be shifted toward theright in the piston chamber in opposition to the spring 207, therebymoving the valve 199 into engagement with the seat 193. When the valve199 engages the seat 193 it overlies and covers the annular groove 214,thereby disconnecting the exhaust passage 215 from the compartment 180a.

The piston continues to move toward the right after engagement of thevalve 199 with the seat 193, as is permitted by the shifting of thevalve carrier 201 on the spacer portion 204 of the screw 202, and thiscontinued movement of the piston causes the stem 206 to engage the valve194 and shift the same away from the valve seat 192. The opening of thevalve 194 permits pressure fluid from the supply reservoir 15 to flowthrough the pasage 191, through the compartment 180a, and then throughthe passage 216 and the pipe 24 to the brake cylinder 16 to cause aservice application of the brake.

When the brake application being made is not an emergency application oris less than a full service a plication, the valve 100 is promptlyreclosed after the delivery of pressure fluid from the auxiliaryreservoir 31 to the application chamber 32 and the relay valve means 35.To explain this reclosing it is pointed out that the delivery ofpressure fluid from the auxiliary reservoir to the application chamberupon opening of the valve 100 causes a decrease in auxiliary reservoirpressure which results in a pressure differential between the auxiliaryreservoir and the brake pipe such that the service pist n 33 is therebyshifted toward the left to reclose the valve 100.

The pressure fluid which is supplied to the compartment 179a of therelay valve mechanism 35 from the auxiliary reservoir 31 can be suppliedto this compartment directly, as in the modified construction of Fig.15, or can be supplied to this compartment through the applicationchamber 32 or in conjunction with the charging of the applicationchamber. In the construction illustrated in Figs. 2, 4 and 5, thepressure fluid is supplied to the compartment 179a of the relay valvemeans through the chamber 182 of the application chamber vent valve 176substantially simultaneously with the charging of the applicationchamber. The valve chamber 182 is formed so as to consist of the twocompartments 182a and 182b. An annular valve seat 218 formed on orsupported by the carrier 174 extends around the wall of the chamber 182at'the junction 'of the compartments 18221 and"182b'. "The passage99*extending from the auxiliary reservoir is'connected with thecomp'artment 182aand the'passage 217 which 13 extends to the compartment179a of the relay valve mechanism 35 is connected with the compartment18212.

The compartment 182a of the vent valve chamber 182 is connected with theapplication chamber 32 through a passage 219 and a guide opening or bore220. The compartment 182b is connected with the atmosphere through apassage 221 and the exhaust chamber 39. A valve seat 222 is formed on orsupported by the carrier 174 on the side thereof adjacent the exhaustchamber 39 and extends around the passage 221.

The vent valve 176 is located in the compartment 182a and is carried byan actuating stem 223 which extends into the chamber 39 through thepassage 221. The valve 176 is engageable with the seat 218 but isnormally held in its open position by a spring 224. A second valve 225carried by the stem 223 and located in the exhaust chamber 39 isnormally held in engagement with the seat 222 by the action of thespring 224. The valve stem 223 includes an extension 226 which isslidable in the bore 220 and has a groove or fiat 227 formed thereon andextending for a portion of its length. 'The stem extension 226 is of asize relative to the bore 220 such that a clearance or tolerancetherebetween provides a leakage space forming a somewhat restrictedconnection between the compartment 132a and the application chamber 32through which the latter can be charged.

When the pressure fluid is supplied to the compartment 179a from theauxiliary reservoir 31, as explained above, it passes quickly throughthe valve chamber 182 and begins to act on the relay valve mechanismeven before the application chamber becomes fully charged. The finalvalue of the pressure thus supplied to the relay valve means will, ofcourse, be the pressure to which the application chamber becomes chargedthrough the leakage space around the stem 226 and the passage 219. Atthis time the vent valve 225 is in engagement with the seat 222 and thevalve 176 is in its open position as shown in Figs. 2 and 5.

With respect to the application chamber 32 it should be explained thatthe volume of this chamber is such that when a given portion of thepressure fluid in the auxiliary reservoir 31 is supplied thereto by theopening of the valve 100, the resulting pressure in the applicationchamber will be of a value to act on the relay valve mechanism 35 tocause a brake application of the desired force to be. produced.Therefore, by making brake pipe pressure reductions of different valuesthe engineer can cause the valve 100 to be opened for different amountsand this, acting in turn to cause the application chamber to be chargedto different pressure values, will result in braking forces ofcorresponding dilferent desired values to be developed by the brakecylinder 16.

At the time that the valve 194 is opened by the stem 206 of the piston185 to cause pressure fluid to be supplied to the brake cylinder 16 fromthe supply reservoir 15, as explained above, there is little or nopressure in the chamber 180a of the relay valve means 35. .Whilepressure fluid is being supplied to the brake cylinder 16, supplyreservoir fluid is also being supplied to the chamber 180a and acts onthe diaphragm portion 183. When the pressure on the diaphragm portion183 balances the application chamber pressure acting on the diaphragmportion 183a in the chamber 179a, the spring 195 recloses the valve 194to thereby discontinue the flow of supply reservoir fluid to the brakecylinder 16 and since the brake cylinder exhaust valve 199 remainsclosed the fluid previously supplied to the brake cylinder will beretained therein for holding the brake in the applied condition. Theapparatus is now in service lap position.

Release after service application {The first step in the release of thebrake after a service and emergency pistons 33 and 34 to the positionsshown in Figs. 2, 3, 6 and 7 and at which time the emergency piston stem133 unseats the valve to permit supply reservoir pressure to be returnedto the brake pipe to assist the releasing operation. During such releaseof the brake after a service application, the pressure in thecompartment 179a is vented to the atmosphere through the vent valvedevice 111 which, as explained above, is opened by motion transmittedthrough the lever 120 in response to release actuation of the servicepiston 33. This permits the spring 207 and fluid pressure in compartment180a to impart a return stroke to the piston and to transmit returnmovement to the piston 184 through the rocking lever 209. The returnmovement of the piston 185 moves the valve 199 away from the seat 193thereby uncovering the annular groove 214. When the groove 214 is thusuncovered, the brake cylinder passage 216 is connected with the exhaustpassage 215 through the compartment 180a whereupon pressure fluid isvented from the brake cylinder to atmosphere to permit the release ofthe brake.

Release after emergency application If the application of the brake waseither a service application or an emergency application, the release ofthe brake can be satisfactorily accomplished by the venting of thecompartment 179a of the relay mechanism 35 through the vent valve device111 which is opened by the release movement of the service piston 33, asexplained above. If the application of the brake was an emergencyapplication, it may sometimes be desirable to vent the compartment 179abya manual venting operation for causing pressure fluid to be exhaustedfrom the brake cylinder 16 for releasing the brake. One instance of whenthe manual venting of the compartment 179a is desirable for releasingthe brake, occurs when a car is cut out of a train as during switchingoperations. At this time the brake pipe connections of the car arebroken and the resulting rapid venting of the brake pipe causes anemergency application of the brake. By manually venting the compartment179:: the brake can be released following such an emergency application,as will now be explained, without venting the application chamber or theauxiliary and supply reservoirs.

This manual venting operation actuates the valve stem 223 in an outwarddirection relative to the chamber 182, that is to say by movement towardthe left as seen in Fig. 5, thereby closing the valve 17 6 and openingthe valve 225. The opening of the valve 225 connects the compartment179a with the vent chamber 39 through the passage 217, the compartment182!) and the vent passage 221.

When the valve 176 is moved into engagement with the seat 218 by thismanual venting operation the stem 226 is partially retracted from thebore 220, thereby moving the flat 227 far enough to extend partway intothe compartment 182a, thus connecting the application chamber 32 withthis compartment through the passage 219. The pressure from theapplication chamber acting on the valve 176 holds the latter against theseat 218, thereby preventing the loss of pressure fluid from theapplicatoin chamber and making it unnecessary for the operator tomanually hold the valve 225 in its open position. While the valve 176 isthus held in engagement with the seat 218, the passage 99 will bedisconnected from the vent passage 221 and loss of the pressure fluid inthe auxiliary reservoir at this time will also be prevented.

The manual actuation of the valve stem 223 in the accomplishment of theabove described venting and brake releasing operation can be producedthrough a lever 228 and a push rod 229. The lever 228 is rockablyfulcrumed on a fulcrum lug 230 of the carrier 174 and has a forked end231 which straddles the valve stem 223 at a point outwardly of the valve225. This forked end of the lever 228 engages in a reduced portion 232of the valve 225 to provide an operating connection with the valve stem-15 223 on which the valve 225 'is' secured by means of the nut'233.

Th'e'other end of the lever 228 has an opening 234 in which the reducedend 235 of therod 229 engages. An annular thrust seat 236 formed on thisend of the lever 22?) extends around the opening 234 and is engaged by awasher 237 which is slidably mounted on the reduced portion 235 of thepush rod 229. around the reduced red portion 235 has one end in seatingengagement with a seat formed by a washer 239 and a shoulder 240. Thespring 238 is of such stillness that when inward axial movement isimparted to the rod 229, the spring will not be initially flexed to anyappreciable extent but will cause thrust to be applied to the seat 236of the lever 228, thereby rocking this lever on the fulcrum lug 23% andproducing an outward movement of the valve stem 223 for causing theabove-explained opening of the valve 225 and closing of the valve 176.When the valve 176 has been closed by engagement'with the seat 218,further outward movement of the valve stem 223 will be prevented and ifcontinued inward axial movement is imparted to the push rod 229, thespring 238 will yield and the reduced portion 235 will move inwardlythroughthe opening 234 or" the lever 228. This relative movement of thereduced portion 235 inwardly through the opening 234 is used to actuatethe supply reservoir vent valve 175- as will be further explainedhereinafter.

luward axial movement of the push rod 229 can be imparted thereto by arockable actuating member or lever 241 which is rockably engaged in aseat 242 of the intermediate hcusing section 28. The actuating member241 includes a lever portion 243 extending outwardly from theintermediate housing section 28 through the opening 244 of the latter.Tilting movement can be imparted to the lever portion 243 by manuallygrasping the same, or through 'a pull rod or pull wire attached thereto,and such tilting movement will cause the head portion 245 to reactagainst the seat'242 to' thereby produce an inward movement of thisactuating member. An operating connection between the actuating member241 and the push rod 229 can be formed by the engagement of a roundedhead 246- of the push rod in a rounded socket 247 or the actuatingmember.

The inward movement of the actuating member 241 which is produced by thetilting of this member, as just described, imparts an inward'axialmovement to the push rod-229. An outward or return movement of the pushrod 229 is produced-by a spring 248 which is disposed around this rodand has its opposite ends inengagement with the spring seats 249 and250. is mounted on the push rod 229 and bears against the head 246thereof. The spring seat 256 bears against a lug 251 of the intermediatehousing section 28 and is retained in place by engagement of a portionof the seat in an opening 252 provided in this lug and through which thepush rod229 extends.

Whenever it is found desirable to vent the pressure out of the supplyreservoir 15, this ca'n'be'done by means of the above-mentioned ventvalve 175. This vent valve is located in the valve chamber 181 and isnormally held in engagement with a valve seat'253 by means of the spring254. The valve seat 253 extends around a passage 255 which connectsthe'chamber 181 with theexhaust chamber 39. The valve 175 has a stem175a which extends through and is slidable in an opening of the carrier174. When the valve 175'is opened, pressure from the supply reservoir 15flows through the pipe 23, the passage 212 and passage portions 213a"and213cinto the chamber 181 and then through the passage 255 to theexhaust chamber 39." t

The vent valve 175 is mounted on the carrier 174 so that the valve stem175a will have its outer end located opposite from and adjacentto theinner end of the push rod 229. "When the actuatingmember 241' is tiltedto im part inward axial inovement1o the'push rod 220, as

A spring 238 disposed- The Spring seat 249 explained above, and theinward movement of the push rod is greater than-is needed toactuate thevalves 176- and 225i theinn'e'rend of-the push rod will then engage thevalve stem -175a'and will open the supply reservoir vent valve 175. Theventing of the supply reservoir in the'm'anner just explained continuesas long as the ventvalve' 175 is manually held open by the push rod229.-

When this venting has continued for the desired length of time, theactuating member 241 is released to permitthe push rod 229 to beretracted bythe spring 248, whereupon the vent valve 175 will beclbsedby the spring 254.

I Auxiliary valve devices I The valve devices embodied in the controlvalve mechanism 14 include a third stage emergency valve 256 and anemergency limiting valve 257 (see-Figs. 2 and 3) and also includeanauxiliary reservoir quick charging valve 258, an auxiliary reservoircheck valve 259 and a supply reservoir charging valve 260 (see'Figs. 2and 5). The valves just mentioned are all located on the carrier 42inarcuately spaced relation to each other so that these valvesconstitute an annular row surrounding the emergency piston chamber 59.When these valves are disposed in' thislocation an extremely compactarrangement andc'onstruction is provided, as shown in Fig. 8 ofthedrawings.

The third stage emergency or equalizing valve 256 is formedjin part, bythe portion 261 of the diaphragm 62 on'which this valve member ismounted. This third'stage emergency valve is locatedin a chamber 262formed by portions of the carrier 42, the adapter 45 and the body 46 andwhichchamber is divided into compartments 262a and 26212 by'thediaphragm portion 261. The-compartment 262a'is connected with a chamber263 of the intermediate housing section 2:; by means of the passage'264and the chamber 263 is, in turn, connected with the supply reservoir15'by the passages 265 and 212 and the pipe 23. A valve seat 256a isformed on or supported by the carrier'42 "so as to be located in thecompartment 262a in'surr'ounding relation to the passage 264:and thevalve member256 is normally held in engagement with this seat by aspring 266 'located'in the compartment- 26%. The pressure of thespring-266 is applied to the valve member 256 through the diaphragmportion 261 and througha cup-shaped spring seat 267 which isslidable inthe compartment262bf The compartment 26211 iscontinuously connected withthe compartment 63 of the emergencypiston chamber 59 by the passage 268.A passage 269 communicates with thecompartmen't 262a and extendstherefrom'to the emergency limiting valve 257.

The emergency limiting valve device 257 includes a valve member-257a(see Fig.3) carried'by-a diaphragm portion270 andlocated in a valvechamberZ'Zl-formed in the" carrier 42. The valve member-257acooperateswith'a valve 'seat272*surroundhi the passage 269; The diaphragm portion270-extends across the valve chamber 271: and divid'es -the same int'ocompartments 271a and 271i). The'compartment' 271 is in opencommunication-with a passage 273'by which it is connected directly withthe passage 9 and with the compartment 167 of the'quick-serviceventvalve'means; The compartment 27'lb is -in-' direct communicationwiththe vent chamber=11( l.

- The emergency limiting valve device 257 also includes a plunger or-'actuating stem= 25712 which is slidable in the body 46' and has itsinner end in engagement withthe diaphragm portion 279. The outer end'ofthe stem 257b extends into a chamber 274 formed between portions of thebody 46 and the cover 47" and carries a head 275. The chamber 274 isdivided into compartments 274a and274b by a portion 276 of the diaphragm52; The head 2'75 and a compression spring 275a acting thereon arelocated in the compartment-274a and this spring li'oldstlie Stern 2571)in a retracted position so that the assume 17 valve member 257a isnormally in an open position. The compartment 274b is connected with theapplication chamber supply passage 99 by the passage 277 such that thediaphragm portion 276 is acted upon by application chamber pressuretending to close the valve member 257a. The spring 275a is of suchstiflness, however, that it will hold the stem 257b in its retractedposition against the normal pressure of the application chamber but whenthe application chamber pressure is increased by the admission of supplyreservoir pressure thereto during an emergency application, this springwill be flexed and the stem 257b will be moved inwardly to close, orpartially close, the valve member 257a. The character of the spring 275aisv preferably such that when the application chamber pressure reaches apredetermined maximum value the valve member 25711 will be moved to itsclosed position. Charging The auxiliary reservoir quick charging valve258 is located in a valve chamber 278 of the carrier 42 and isengageable with a valve seat 279 formed or mounted on the carrier. Thevalve seat 279 extends around a passage 280 which connects the valvechamber 278 with a diaphragm chamber 281. A diaphragm portion 282extends across the chamber 281 and divides the same into compartments281a and 28111. The valve 258 has a stem 258a which is slidable in thecarrier 42 and extends into the compartment 281a to be engaged by thediaphragm portion 282. A spring-283 located in the compartment 281b actson the diaphragm portion 282 through a spring seat 284 and holds thevalve 258 open whenever the pressure in the auxiliary reservoir is at avalue below approximately fifty pounds per square inch. A spring 285located in the compartment 281a acts on the valve stem 258a to draw thevalve 258 toward engagement with the valve seat 279 but is a relativelylight spring so as not to prevent the valve from being held open by thespring 283 when the pressure of the auxiliary reservoir is below thevalue mentioned above. The compartment 281b is at all times vented toatmosphere inasmuch as it is connected with the vent chamber 110 by thepassage 2810.

The valve chamber 278 of the auxiliary reservoir quick charging valve isconnected with the brake pipe chamber 57 by a passage 286 so that whilethe valve 258 is held open by the spring 283, fluid pressure from thebrake pipe 13 will flow through the passage 286 to the chamber 278 andthen through the passage 280 into the compartment 281a. From thecompartment 2810 the fluid pressure flows through a passage 287 into achamber 288 of the carrier 42 and then past the auxiliary reservoircheck valve 259 into the auxiliary reservoir 31. The fluid pressurebeing supplied to the auxiliary reservoir through the compartment 281aacts on the diaphragm portion 282 and whenthe pressure of the fluid inthe auxiliary reservoir increases to approximately the fifty pounds persquare inch value mentioned above, the spring 283 will be compressed tothereby permit the spring 285 to close the valve 258.

The fluid being supplied to the auxiliary reservoir 31 past the quickcharging valve 258 flows into the auxiliary reservoir from the chamber288 through the passage 289. This passage is controlled by the checkvalve 259 which cooperates with a valve seat 290 provided on the carrier42 and surrounding the passage 289. The check valve 259 has a stem 259awhich is slidable in the carrier 42 and extends into the chamber 288. Aspring 291 located in the chamber 288 acts on the stem 259a to normallyhold the check valve 259 in a closed position in engagement with theseat 290. The check valve 259 is readily opened by the pressure fluidflowing into the auxiliary reservoir past the quick charging valve 258but when the auxiliary reservoir pressure reaches the fifty pounds persquare inch value mentioned above and the quick charging valve 258 isclosed, the check valve thereafter remains seated and prevents abackflow of a Cl pressure fluid out of the auxiliary reservoir throughthe passage 289. j

The supply reservoir 15 is charged with pressure fluid which is suppliedthereto from the brake pipe through the auxiliary reservoir 31. For thispurpose a valve chamber 292 (see Fig. 5) which is adapted to beconnected with the auxiliary reservoir is in open communication with thesupply reservoir 15 through a passage 293, the chamber 263, the passages265 and 212 and the pipe 23. The connection of the chamber 292 with theauxiliary reservoir 31 is. controlled by the outwardly opening supplyreservoir charging valve 260. The valve 260 is located in the valvechamber 292 and cooperates with a valve seat 294 formed or mounted onthe carrier 42 and extending around the passage 295. .The valve 260 hasa stem 260a which extends through and is slidable in the carrier 42.Whenever the pressure in the auxiliary reservoir 31 falls below that towhich the supply reservoir 15 has been charged, the valve 260 will beclosed by the supply reservoir pressure and by the action of a lightspring 26% and will prevent a return flowof fluid out of the supplyreservoir.

Load responsive mechanism The improved air brake apparatus hereindisclosed is automatically responsive to changes in the load of therailway car 10 so that the braking force developed by the brake will besubstantially in proportion to the load carried by the car. The amountof the braking force developed by the brake is dependent upon thepressure of the fluid supplied to the brake cylinder 16 and this can bevaried by adjustment of the relay valve mechanism 35. The adjustment ofthe relay valve mechanism is accomplished by shifting the fulcrum pin210 which is carried by a fulcrum pin bracket 211 so as to vary theefiective lever arm values of the arms 209a and 20% of the rocking lever209. Such shifting of the fulcrum pin 210 is efiected automatically by ahydraulic pressure responsive device 212 embodied in the load responsivemeans 213 which will be described next.

The fulcrum pin bracket 211 is carried by a cup-shaped plunger 296 whichis shiftable in response to variations in hydraulic pressure occurringin the working chamber 297 of a hydraulic cylinder or bulb 298. Thecylinder 298 is suitably mounted on the intermediate housing section 28and is located in the fulcrum chamber 38 thereof. The cylinder 298 isformed, in part, by a metal shell 299 and, in part, by a flexible wall300 formed of rubber or other suitable flexible material. The flexiblewall 300 can be connected with the metal Shell 299 by having an edgebead 301 locked in an annular channel 302.

Theplunger 296 is provided with a stern 303 which 15 slidable in a guidesleeve 304; I "-If desired, the stem 303 may have spaced bushings 305connected therewith for mounting this stem'in the guide sleeve. Theplunger 296 is maintained in coaxial alignment with the cylinder 2 98 bythe cooperation of the stem 303 with the guide sleeve 304, and theplunger is held in seating engagement with the flexible wall 300 bymeans of a spring 306 which is disposed around the guide sleeve. Theplunger 296 is held against arcuate shifting about the axis of the stem303 by means of a fixed pin 307 mounted on the housing section 28 andextending into an axial slot 308 of the plunger.

The guide sleeve 304 extends into the fulcrum chamber 38 through anopening 309 of the housing section 28. The guide sleeve is carried by acover 310 which is adapted to be bolted or otherwise suitably connectedwith the housing section 28 in overlying relation to the.

opening 309. A collar 311 forms a seat for the outer end of the spring306 and is slidable on the guide sleeve 304. The tension of the spring306 can be adjusted by shifting the collar 311 along the guide sleeve304. This adjustment of the collar along the guide sleeve can beaccomplished by providing the collar with a pair of pins 312 whichextend'through slots 313 of the sleeve and are engaged by an adjustingnut 314. The nut 314 engages an internalthread 3150f the guidesleeve andis provided with a wrench socket 316 to which a suitable adjusting toolcan be applied for screwing the-nut inwardlyor outwardly of the guidesleeve. Access to the adjusting nut 314 is had through an opening 317 ofthe cover 310 and which opening is normally closed by a removable plug318. The plug 318 has a wrench socket 318:: therein of the same size andshape as the wrench socket 316 so that this plug can be loosened ortightened by the same tool as is used on the nut314.

The load setting for the relay valve mechanism 35 is determined by theposition to which the plunger, 296 is moved and this, in turn, dependsupon the volume of hydraulic pressure fluid'which' is forcedflinto thechamber 297 through the pipe 27in opposition to the spring 306. Thehydraulic pressure fluid supplied to the chamber 297 is deliveredthereto from the hydraulic cylinder devices 25 and 26 which are of theexpansible chamber or bellows type and are located at opposite sides ofthe truck 10. These hydraulic cylinder devices are mounted on a sprungpart of the car, such as the bolster 12, and engage unsprung portions ofthe car, such asthe side frames 11, so that the relative movement whichtakes place between the sprung and unsprung portions due to changes inthe loading of the car will cause variable amounts of the hydraulicpressure fluid to be delivered by the devices 25 and 26 to the chamber297 ofthe hydraulic cylinder 295. By providing two of the generatingdevices 25 and 26 and locating the same at opposite sides of the truckof the car 10, the effects of lateral rocking of the car body on itssupporting trucks on the amount of hydraulic pressure fiuid' beingsupplied to the cylinder 298 will be eliminated.

When the load of the car is increased the devices and 26 will be furthercontracted and will cause an increased amount of the hydraulic pressurefluid to be transmitted to the chamber 297 of the pressure responsivedevice 212 to alter the setting of! the relay valve mechanism 35 bymoving the fulcrum pin 210' upwardly as seen in Fig. '4. When the loadof the car is. decreased, the cylinder devices 25' and 26 will bepermitted to expand and a corresponding amount of hydraulic pressurefluid will be transmitted thereto from the chamber 297 and this willpermit the spring 30610 alter the setting of the relay valve mechanism35 by moving the plunger 296 and the fulcrum pin 2l0idownwardly.

When the fulcrum pin210 is moved upwardly in re sponse to a carloadincrease, the lever arm 209a is thereby lengthened. and the leverarm209b' is correspondingly shortened. During an application of thebrake the pressure fluid supplied to. compartment. 179a of the rei'ayvalve means 35 acts through. the fuicrumed' lever 209, as explained,above, to cause the valve 194 to be opened for supply reservoir fluid tobe supplied to the brake cylinder. At this time pressure 'of' the supplyreservoir fluid builds up in the compartment 189a and shifts the piston185 to permit the valve 194 to reclose, as also explained above. Whenthe lever arm 209 has been shortened by an increase in the car load, agreater pres sure will need to build up in the compartment 180a to shiftthe piston 185 against the pressure acting in the compartment 179a topermit reclosing of the valve 194, and such greater pressure. will alsoact in the brake cylinder to cause a stronger braking forceto bedeveloped.

The conduit which transmits the hydraulic pressure from the generatingdevice '25 to the pressure responsive device 212 includes the previouslymentioned pipe 27 and the branch pipes 25:: and 26a. tachably connectedwith the control valve mechanism 14 by means of the connection 320'forfacilitating inspection and repair operations on the apparatus. Similardetachable connections are provided between the branchpipes- 25a, 26aand the hydraulic pressure. generating devicesv The pipe 27 is de- 25,26. In order to prevent the escape. of the hydraulic fiui'clfrom thepipes and the pressure devices when the pipes are disconnected, thesepipes. are provided with valved fittings which form these detachableconnections.

As shown in-Fig. 13, the setting of the load responsive mechanism 213 ofany car of the train can be quickly and easily checked or determined bya crewman by a simple gauging operation. In doing this the plug 318 isunscrewed to afford access to the passage of the guide sleeve 304 and agauge member 321 of the measuring stick type isinserted'. The gaugezhasappropriate graduations 321a thereon and when its inner end engages thepiston stem 303 a portion of the gauge will remain in outwardlyprojecting relation from the guide sleeve 364 to indicate the setting ofthe load responsive mechanism.

Detailed operation The operation of this improved airbrake. apparatushasalready been partially explainedin the foregoing description but amore complete explanation of the operation of the apparatus will now begiven. When the con trol valve mechanism 14 isin the conditioncorresponding with the release and normal charging position illustratedin Figs. 2, 3., 5 and 6 of thedrawings, the auxiliary reservoir 31 isbeing charged from the brake pipe 13 through the passage 58, brake pipechamber 7, compartment 54 of the service piston chamber 49, through thepassage 67a, valve chamber 74 and past the charging valve 84 which is,then in its open position, through the axial passage 79, the radialports and past the elasticcheck valve member 98 into the auxiliaryreservoir. If the condition of. the air brake apparatus happens to beone. in, which the auxiliary reservoir 3.! is empty, the charging ofthis reservoir will initially take place as a quick charging operationduring which air will be rapidly supplied to, this reservoir (see Fig,5) from the brake pipe chamber 57 through the passage 236, past thequick charging valve 258 which is then being held in its open positionby the spring 283, through the passage 280, compartment 281a of thechamber 281, passage 287, valve chamber 288, passage 289' and past thecheck valve 259 into theauxiliary reservoir.

When the. quick charging operation progresses to the point where thepressure in the auxiliary reservoir has built'upto-a value ofapproximately 50 pounds per square inchthispressure acting on thediaphragm portion 282 of the chamber 281 will assist the spring 235 andcause closing of the quick charging valve 258. Therefore the charging ofthe auxiliary reservoir will ordinarily take place through the valvechamber 74 of the service piston 33, through the ports 95, and past thecheck valve 98. as just, explained above. When the charging of theauxiliary reservoir through the ports 95 has resulted in the pressurebeing built up to the pressure of the brake pipe. the check valve 98will remain closed and equalization of the auxiliary reservoir pressurewith brake pipe pressure. asfluctuations occur in the latter, will takeplace through the continuously open restricted port 96.

While the auxiliary reservoir 31 is being charged, the supply reservoir15 and the emergency and release control chamber 40 are also beingcharged and by the time that the auxiliary reservoir is fully chargedthe supply reservoir and the emergency and release control chamher willalso be fully charged. The supply reservoir 15 isrcharged' fromtheauxiliary reservoir 31 by the flow of air from the latter through thepassage 295, past the check valve 260, through passage 293, chamber 263,and through passage 65, and pipe 23 into the supply reservoir.

The emergencyv and release control chamber 40 is charged from thesupply-reservoir 15 While the value 1 .0 (see Figs. 3 and 7) is beingheld open by the hollow stem 133 of the emergency piston 34 which hasbeen shifted to the right: by-the increasing brake pipe pressure. Theflow of air for this purpose is traced from the supply reservoir 15through pipe 23, passages2l2 and 265 into chamber 263, then past valve140 and around the outside of the emergency piston stem 133, through thecounterbore 173 and grooves 172 which are then in overlapping relation,into the compartment 63 of the emergency piston chamber 59 and throughpassage 65 into the emergency and release control chamber 40.

When a service application of the brake is made, the engineers brakevalve is actuated to vent pressure from the brake pipe 13 and theresulting pressure drop is transmitted to the control valve mechanism 14of each car of the train and results in a decrease in pressure in thecompartment 54 of the service piston chamber 49 and in asimilar-decrease of pressure in the compartment 64 of the emergencypiston chamber 59. A pressure difierential is thereby created betweenthe compartment 64 and the compartment 63 with which the control chamber40 is in direct communication. This pressure diiferential moves theemergency piston 34 toward the left, as seen in Figs. 2, 3 and 7,causing the piston member 61 to engege the push pins 164 of thequick-service vent valve 155. This movement of theemergency pistoncontinues for a distance sufiicient to shift the pins 164 and open thequick-service vent valve 155 but not far enough to cause the piston stem134 to open the emergency vent valve 147.

The opening of the quick-service vent valve 155 on each car of the trainby the emergency piston 34, in the manner just explained, causes brakepipe pressure to be vented locally to atmosphere at each car through thepassages 157 and 157a, past the second quick-service vent valve 165,through the passage 159 and into the vent chamber 110 which leads toatmosphere through the exhaust chamber 39 and the exhaust passage 39a.The venting of pressure from the brake pipe to atmosphere in this mannerat each of the control valve mechanisms of the train, quickly reducesthe brake pipe pressure for producing a service application of thebrakes and eliminates the time delay which would be involved if all ofthe air had to be vented through the engineers brake valve. Thequick-service vent valve 155 remains open during the service applicationof the brake, but as soon as pressure fluid is supplied to theapplication chamber 32 and the relay valve means through the passage 99by reason of the functioning of the service piston 33, as will bepresently explained, such pressure fluid enters the valve chamber 166and closes the quick-service vent valve 165.

The initial venting of brake pipe pressure through the engineers brakevalve and through the quick-service venting means, just explained above,results in a pressure difierential on the service piston 33 in which theauxiliary reservoir pressure existing in the compartment 53 predominatesover the pressure in the compartment 54 and causes the service piston tobe moved toward the right, as seen in Figs. 2, 3 and 6. The abovedescribed movements of the service and emergency pistons 33 and 34result in these pistons assuming the quick-service position in which thequick-service venting valves 155 and .165 are in their open position.

During the movement of the service piston 33 to the quick-serviceposition, the valve 84 will be engaged by the valve seat 85, after whichthis valve will be moved with the piston, causing further compression ofthe spring 87. During this movement of the service piston, the hollowpiston stem 78 will be moved in a direction away from the valve seat101, but the application chamber inlet valve 100 will be maintained inits closed position in engagement with the seat 101 by the spring 89.

When a service reduction has been made and the functioning of theapparatus has progressed beyond the quickservice position to the pointwhere a service application of the brake has actually taken place, theservice piston 33 will have been moved toward the right a sufficientdistance to cause the lost motion to be fully taken up between thehollow piston stem 78 and the head 88a of the plunger 88 carrying theapplication chamber inlet valve 100. The valve will thus be moved awayfrom its seat 101, thereby permitting air from the auxiliary reservoir31 to be supplied to the relay valve mechanism 35 and to the applicationchamber. The extent to which the valve 100 can be opened during aservice application will be limited by the pre-loaded spring 91 whichacts as a stop at this time.

The flow of air from the auxiliary reservoir 31 to the relay valvemechanism 35 and the application chamber 32 takes place through thevalve port 104, the chamber 103, the bent tube and passage 99 to thecompartment 182a of the valve chamber 182. From the valve chamber 182some of the pressure being supplied is delivered to the compartment 179aof the piston chamber 179 of the relay valve mechanism 35 through thepassage 217. At this time the valve 176 is in its open position, asshown in Fig. 5, and the compartment 18211, with which the passage 217is connected, is in open communication with the compartment 182a. Someof the pressure being supplied to the valve chamber 182 is alsodelivered to the application chamber 32 by flowing through therestricted passage provided by the clearance space or tolerance existingbetween the stem 226 and the bore 220, through the groove 227 and thepassage 219 into the application chamber.

The fluid pressure supplied to the compartment 179a of the pistonchamber-179 has acted on the piston 184 and has shifted the same towardthe left and has thereby rocked the lever 209 on the fulcrum pin 210.The rocking of this lever has transmitted motion to the piston 185 andhas shifted the latter toward the right in opposition to the spring 207.This movement of the piston 185 has caused the brake cylinder exhaustvalve 199 to engage the annular valve seat 193 to close the exhaustpassage 214. Movement of the piston 185 has continued after the seatingof the valve 199 on the valve seat 193, causing the stem 206 to engageand open the brake cylinder inlet valve 194. The opening of the valve194 has permitted pressure to be supplied to the brake cylinder 16 fromthe supply reservoir 15 to actuate the brake cylinder and cause aservice application of the brake.

The path of travel of the pressure fluid thus supplied to the brakecylinder 16 is traced from the supply reservoir 15 through the pipe 23to the control valve mechanism 14 and through the passages 212, 213a and213b thereof to the valve chamber 190, then past the brake cylinderinlet valve 194 through the passage 191 to the compartment a of thepiston chamber 180 and then through passage 216 and pipe 24 to the brakecylinder. The fluid being thus supplied to the brake cylinder throughthe compartment 180a also acts on the piston and balances the pressureacting on the piston 184. As long as the service piston 33 remains inthe service position, the application chamber inlet valve 100 will be inopen position and the relay valve mechanism 35 will be maintained in theposition in which the brake cylinder vent valve 199 is closed and thebrake cylinder supply valve 194 is open, and during this time the brakecylinder 16 will hold the brake in its applied position. During the timethat the brake is thus maintained in the applied position, the camshoulder 123 will be disengaged from the bellcrank lever 120 and thevalve member 114 of the application chamber vent valve device 111 willbe maintained in its closed position by the spring 117.

During the functioning of the control valve mechanism 14 to produce theabove described service application of the brake, the emergency piston34 is moved to the left by the pressure of the control chamber 40 actingthereon through the compartment 63, as explained above. This movement ofthe emergency piston 34 is desirable for actuating the quick-servicevent valve 155, but movement of the emergency piston at this timethrough a sufficient distance to unseat the emergency vent valve 147would be undesirable because it would result in an undesired

